Development of high field permanent magnet

Permanent magnets are believed to be applicable only to make small and weak magnets. It is possible, however, to make a magnet with much higher strength than those in the past by introducing a saturated iron pole. Cooling down the magnet further enhances the field strength to a great extent. We have demonstrated that a permanent dipole magnet exceeding a typical permanent magnet more than by factor 3 is possible. A new challenge is to conceive such magnet for an accelerator application where time dependent alternating field is often requested.